Abstract: The triggering of the strong convection process in the warm sector ahead of the front that occurred on March 23, 2023, is analyzed using SA-band dua-polarization radar, FY-2G blackbody brightness temperature (TBB), ground encrypted observation data, routine observation data, and ERA5 reanalysis data, together with the method of synoptic meteorological diagnosis and a method for calculating sea breeze contribution through system wind separation. The results showed that: (1) Before warm-sector convection initiation, forecasters may fail to predict convective events (resulting in false negatives) due to an insufficient diagnosis of triggering conditions within the warm sector, even when favorable environmental parameters are present. (2) In the background of warm low pressure development and low-level warm advection forcing, mid-scale convergence in the warm sector ahead of the front strengthens in the afternoon, and the convergence of southwest dry warm airflow and onshore wet cold airflow appears. Calculating the contribution of sea breeze through system wind separation confirms that Nanning is affected by sea breeze in the afternoon. The sea breeze strengthens and penetrates about 100 km inland, bringing water vapor and shallow cold advection, which work together with low-level mesoscale convergence to trigger convection. (3) The three body scattering spikes (TBSS) of cells A and B exhibit obvious precursor characteristics before extending. The radar echo exhibits short spikes, characterized by a robust reflectivity core (Zh; 45~65 dBZ) collocated with minimal differential reflectivity (ZDR≈0 dB) and slightly depressed cross-correlation coefficient (CC; 0.9~0.95). At the initiation region, weaker reflectivity (Zh; 10~25 dBZ) coincides with anomalously elevated ZDR values (6~7 dB), low and noisy CC (0.6~0.9), and near-zero or missing specific differential phase (KDP). Notably, the weak echo segments at mid-to-end remain not yet stretched out.The TBSS feature is that the reflectivity core (a hail core) is extremely strong (Zh=65~71 dBZ, CC small, ZDR negative, KDP void), characterized by a long and flame-like weak echo extending radially in front of the reflectance core. The corresponding correlation coefficient(CC) and radial velocity (V) are both small and noisy. ZDR presents a"big first, small later" pattern. In the mature stage, cell B presents super-individual hailstorm cloud structures such as overhangs, a bounded weak echo region (BWER), and double vortex structures. (4) The combined use of polarization parameters such as Zh, ZDR, CC provides a more accurate signal for identifying TBSS and discovering precursor characteristics of TBSS, which is beneficial for early warning of hail.